Carton structure



C. LAKE CARTON STRUCTURE Dec. 5, 1967 2 Sheets-Shea*b l Filed Dec. 2l, 1965 C. LAKE CARTON STRUCTURE Dec. 5, 1967 2 Sheets-Sheet Filed Dec. 2l, 1965 ff. wm: m. CONNIE LAKE United States Patent O 3,356,284 CARTON STRUCTURE Connie Lake, Pittsford, N.Y., assignor to Mobil Oil Corporation, a corporation of New York Filed Dec. 21, 1965, Ser. No. 515,339 Claims. (Cl. 229-45) ABSTRACT OF THE DISCLOSURE A molded egg carton comprising a top section and a bottom cellular section integrally connected together along a longitudinal hinge-line, and a pair of longitudinally extending locking flanges integrally molded to each of the respective carton sections, said flanges being located along the longitudinal edge of said top carton sections and said bottom cellular section remote from said hingeline and adapted for interlocking relationship whereby said carton sections may be releasably locked together when said carton is in a closed position.

The present invention relates to improvements in egg cartons and more particularly to an integral means for releasably locking together the cover and bottom sections of the carton.

The locking feature of the cartons of the present invention offer distinct advantages over the prior art locking means for such cartons as hereinafter discussed. In the past it has been known to effect a locking together of the cover and bottom sections utilizing extraneous means, e.g. adhesive materials such as glue or tape. Such an arrangement sutfers from the disadvantage that once the carton has been opened it is inconvenient and diiicult, if not impossible, to again effect a locking closure thereof Without reapplying said adhesive means. This drawback, i.e. lack of a readily reusable and easy opening, releasable, locking mechanism in earlier carton structures, has been partially solved by certain prior art cartons which employed locking means that are built into the carton as 4an integral part thereof. Such means comprise projecting tab or lug members adapted for insertion into mating recesses or slots to secure the top and bottom sections of the carton in a closed relationship. However, such locking means have not met with complete success for various reasons, chietly the amount of manipulation required in opening and again in reclosing and locking the cartons. Additionally, such prior .are locking means failed to give a suciently positive locking action whereby inadvertent opening of said top and bottom sections often resulted.

The present invention provides a molded egg carton, having a top cover section and a cell-containing bottom section, a bracing and locking flange which is integral with the cellular bottom section of the carton and which flange telescopes slidingly upwardly into locking engagement with means provided in the cover section as the cover is brought down toward the bottom section for closure of the carton. Said means comprises .a locking flange integral with a side margin of the cover section thereby providing an interlocking member for engagement with the bottom locking flange when the carton is in a closed position.

A wide variety of materials may be employed in the fabrication of the carton structures of the present invention, for example, molded paper pulp, pasteboard, plastic, and the like. A preferred material has been found to be thermoplastic foam such as, for example, foam polystyrene, although other polymers such as polyethylene, polypropylene, polyvinyl chloride and the like are also useful. A single preferred embodiment of the present invention is presented, for purposes of illustration, in the attached drawings showing an egg carton as embodied f Patented Dec. 5, 1967 herein produced by match molding from a sheet of polystyrene foam. However, the invention may be incorporated in other modified carton forms as hereinafter described.

In the, drawings:

FIGURE 1 is a top plan view of a molded carton in an open position.

FIGURE 2 isa bottom plan view of a molded carton of the present invention in an open position.

FIGURE 3 is a view in transverse vertical section of the open carton along the line corresponding to line 3-3 of FIGURE l.

FIGURE 4 is a front elevational view of the carton in section showing the relationship of the carton locking means as the carton sections are being drawn into closed relationship.

FIGURE 5 is a front elevational view of the carton in section when the carton sections are in a closed position.

FIGURE 6 is an end-elevational view of the carton taken along line 6-6 of FIGURE 4.

FIGURES 7 and 8 lare fragmentary Iviews in vertical section along lines 7-7 and 8 8 respectively of FIG- URE 5. y

FIGURE 9 is a fragmentary view in horizontal section along line 9-9 of FIGURE 8.

As more clearly illustrated in FIGURES 1 and 2 of attached drawings, the carton construction of the present invention comprises a top section 11 and a bottom cellular section 12, integrally hinged at 13 along a common longitudinal margin of each of said sections. The cellular bottom section 12 comprises a series of egg receiving cells 14. Along the longitudinal edge of said bottom cellular section 12, opposite longitudinal hinge 13 and integrally hinged thereto, is bottom cellular section locking ange 15 which extends substantially the entire length of said bottom cellular section 12. Bottom locking flange 15, normally positioned in a horizontal plane, is rotatable about the longitudinal axis of connecting hinge 16 whereby, when the carton sections are in a closed position, said bottom locking ange is rotated about the hinge axis 16 to a substantially vertical position inside of the front wall of said top carton section. The carton top section 1I comprises front wall 17, joined to rear wall 18 by side wall members 19 and 19', respectively. Bottom longitudinal edge 20 of rear wall 18 is continuously joined to a longitudinal marginal edge of the bottom cellular section 12 by integral hinge member 13. The front wall 17 of top section 11 has integrally hinged, along the bottom longitudinal edge 22 thereof, top locking ange member 21 which extends substantially the entire length of said front wall bottom edge 22. Top locking flange member 21, which normally extends in a horizontal plane is rotatable around the longitudinal axis of integral hinge 22 whereby when the top and bottom cellular sections are in closed relationship, top locking ange 21 is in a substantially vertical position adjacent to the inside surface 23 of front wall member 17.

As more clearly illustrated in FIGURES 7 and 8, the upper edge of bottom locking flange 15 has a longitudinally extending projecting ridge 24, which projects away from the carton interior when the carton sections are in a closed relationship. Ridge 24 may extend continuously across substantially the entire length of the upper edge of bottom locking flange 15, as shown in FIGURE 2 or it may be discontinuous, consisting of a series of discontinuous or unconnected protrusions extending intermittently along the edge of bottom locking ange 15. For a clearer understanding of the novel carton releasable locking arrangement of the present invention, reference is made herebelow to a description of a typical carton closy ing (locking) and opening (unlocking) operation.

3 Closing To effect a locking closure of the carton, bottom locking flange member is rotated about integral hinge 16 to an upstanding or vertical position as illustrated by the dotted lines in FIGURE 5. Subsequently, carton top section 11 is rotated around integral hinge 13 towards closing relationship with bottom cellular section 12. Simultane ously, top locking flange member 21 is rotated about integral hinge 22 whereby said flange is positioned adjacent the inside surface l23 of front wall 17 of top section 11. As the interlocking flange members 15 and 21 are brought into locking engagement as a result of the aforesaid closing operation, the outer surface 25 of the top locking flange 21, i.e. the surface opposite that surface which is now adjacent the inside of 'front wall 17, is slideably cammed over ridge 24 along the upper edge of upstanding bottom locking flange 15, which exerts a pressure against top flange 21 forcing it against inside wall. surface 23. Simultaneously, upstanding bottom locking flange 15 is being telescoped into the interior of said carton sections. As the carton sections meet, around the peripheral edges thereof, ridge 24 finally projects itself over the longitudinal edge 26 of top locking flange 21. As a result of the release of pressure being exerted against top locking flange 21 by projecting rib 24 which was previously forcing said top locking flange inwardly against surface 23, ridge 24 is now cammed over the edge 26 of top locking flange 21 whereby said projecting rib is adjacent the inside wall surface 23 of front wall member 17 along the upper edge thereof as illustrated in FIGURE 7. Since there is a natural tendency for integrally molded bottom locking flange 15 and top locking flange 21 to assume their normally substantially horizontal position as illustrated in FIGURE 3, a positive interlocking of the flange members results, bottom locking flange 15 having a tendency to press outwardly against the surface of top locking flange 21 and top locking flange 21 having a tendency to press inwardly against the surface of bottom locking flange 15 in contact therewith. As shown in FIGURES 7 and 8, when the carton is in a closed position, edge 26 of top locking flange 21 abuts the base of ridge 24 of bottom locking flange 15 and when opening forces are applied in a downward direction, as for example by the weight of eggs contained in cells 14 when the carton is filled with product, the carton sections remain firmly locked in a closed position.

Opening When it is desired to open the carton, the edge 26 of top locking flange 21 must be disengaged from the base of ridge 24 of bottom locking flange 15. This may be quite easily accomplished by merely exerting, simultaneously, a slight upward and outward pressure against the exterior surface of longitudinal hinge 22 while grasping the cartons cellular bottom section 12. This results in edge 26 of top locking flange 21 pivoting about ridge 24 of bottom locking flange 15, integral longitudinal hinge 22 allowing flexure of top locking flange 21 as it rotates about hinge l22 and as the carton sections are being rotated about integral hinge 13 to an open position. The movement of the locking flanges during the opening of the carton sections is illustrated by the dotted lines in FIGURE 8.

When carton sections 11 and 12 are in closed position, the upstanding bottom locking flange member 15, as aforediscussed, is positioned interiorly of the closed carton sections. Although as illustrated in the drawings bottom locking flange member 15 does not contact the inside surface of the top of cover section 11 when the carton is closed, flange 15 may be constructed so that it is extended to engage the inside surface of top section 11 whereby flange 15, in addition to performing a locking function may also serve to brace the top of cover section 11 thereby resisting compression forces exerted on the top and bottom carton sections which may be encountered during handling of the closed carton. However, such contact is not essential and especially so when the locking flanges are provided with appropriate means such as mating frusto-conical projections and recesses which engage and abut against one another thereby preventing said top seetion 11 from telescoping down over said bottom section 12 as illustrated in the drawings. Additionally, flange 15 prevents lateral movement of the top and bottom carton Sections by the tendency of its lateral edges to abut against the inside surface of sidewalls 19 and 19 of top section 11 when such lateral force may be applied to the carton, as for example forces encountered during normal shipping and handling operations.

In a preferred embodiment of the carton structure as illustrated in the attached drawings cover section sidewalls 19 and 19 and 17 and 18 are of scalloped shape, featuring longitudinally spaced outwardly curved, or recessed bays 27 formed by frusto-conical sectional sur faces molded in the sidewalls of the cover section to increase the egg room in the cover section above the egg cells 14 of the bottom section. Intermediate said bays 27, which are generally in alignment with the recess portions of cells 14, are inwardly projecting abutting ledges 28 which abut against abutment ledges 29 intermediate cells 14 ywhen the carton sections are in a closed position. Similarly bottom locking flange member 15 is characterized in that it may have a scalloped shape featuring longiincreased. Intermediate said outwardly curved bays 30,. formed by frusto-conical sectional surfaces molded in bottom locking flange member 15 whereby the egg room in the area adjacent the inside of upstanding bottom locking flange 15 when the carton is in a closed position is increased. Intermediate said outwardly curved bays 30, abutment ledges 31 are formed whereby, when the carton sections are closed and the bottom locking flange 15 is in a vertical position abutment ledges 31 and 29 come into contact thereby supporting said bottom locking flange 15 away from crushing engagement with the eggs retained in cells 14. Top locking flange member 21 may likewise assume the scalloped shape as illustrated in FIGURES l and 2 featuring longitudinally spaced outwardly curved or recess bays 33 formed by frusto-conical sectional surfaces molded in said top locking flange. Thus, when the carton sections are in closed relationship and top locking flange member 21 is rotated to a position adjacent inside surface 23 of top section 11, the surface thereof presents frusto-conical projections 33 for mating engagement into the frusto-conical recesses 34 present in the exterior surface of bottom locking flange 15 when it is in a vertical position. It will be apparent that such an arrangement, i.e. the interengagement of projections 33 with recesses 34, allows for a lateral locking engagement of the top and bottom locking flange members whereby lateral stress forces which may be applied to the exterior of the closed carton are resisted, thereby preventing lateral movement of the carton sections with respect to one another. This lateral locking of the top and bottom locking flanges enhances the inherent resistance to lateral section movement already present in the carton structure by virtue of upstanding bottom locking flange 15 abutting the interior of top section end walls 19 and 19 when the carton is in a closed position. It will be apparent that, although as illustrated in FIGS. 7, 8 and 9 the carton ywhen in a closed position the top locking flange 21 and bottom locking flange 15 are in side by side relationship, it is not necessary that when the carton is in a closed position, the top and bottom locking flanges should be in immediately, adjacent face to face contact. Said locking members may be spaced apart somewhat whereby, although there is no face to face contact as illustrated in the drawings, such spacing of the contacting surfaces of the locking flanges will not adversely affect the locking arrangement of the present invention.

It should be further understood that the scalloped configuration of the locking flanges and sidewalls of carton top section 11 is only a preferred embodiment of carton structures which may employ the unique locking features of the present invention. Moreover, the surfaces of the locking flanges may be flat or planar as well as the surfaces of the sidewalls of the top of the cover section and still allow functioning of the carton locking means of the present invention as hereinbefore discussed.

Additionally it will be apparent that ridge 24 of bottom locking liange may be discontinuous, that is, a plurality of projections may be spaced along the upper edge of bottom locking iiange member 15 rather than a continuous ridge, said projections being adapted to engage edge 26 of top locking flange member 21 when the carton is in a closed position.

Although the present invention has been described with preferred embodiments, it is to be understood that modiications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. In a molded egg carton comprising a top section including a cover having a front wall, a rear wall and two side walls; and a bottom cellular section having a front side, a rear side and tWo ends and connectively hinged to said cover along the margin of the rear side of the bottom section to the margin of the rear side of the cover, the improvement which comprises a locking arrangement for securing said top and bottom sections in a closed relationship, said locking arrangement comprising (l) a bottom locking flange having (a) one of its longitudinal edges hinged to the longitudinal edge of the front side of said bottom cellular section, and (b) an opposite longitudinal edge; spaced-apart recesses located along the length of said bottom locking ange, said recesses being characterized by having a locking ridge located substantially adjacent to said opposite longitudinal edge; and (2) a top locking flange having (a) one of its longitudinal edges hinged to the longitudinal edge of the front wall of said top section; and (b) an opposite longitudinal edge, said top locking ange being positionable inside of the front wall of said top section and substantially in parallel relationship therewith; said top locking liange being further characterized by having spaced-apart projections located along the length of said top locking flange, which projections are adapted when the carton is closed, for mating engagement with said recesses on said bottom locking flange, said bottom locking ange being positionable inwardly toward said connecting hinge whereby, when said carton is closed7 said bottom locking ange is substantially adjacent to the top locking ange and an edge of a projection in the top locking flange abuts against a locking rid-ge on said bottom locking flange.

2. A molded egg carton in accordance with claim 1 wherein when said carton is in a closed position, said recesses located along the length of said bottom locking flange project inwardly toward said connecting hinge; and said projections located along the length of said top locking flange project inwardly toward said connecting hinge.

3. A molded egg carton in accordance with claim 1 which is formed of foam polystyrene.

4. A molded egg carton in accordance with claim 1 wherein the top locking ange contains frusto-conical projections and the bottom locking ange contains frustoconical recesses, said projections and recesses being adapted for mating engagement with one another when the carton is closed.

5. A molded egg carton in accordance with claim 1 wherein the surfaces of the front wall, rear wall and two sidewalls of said top section comprise spaced-apart outwardly curved frusto-conical recess bays.

References Cited UNITED STATES PATENTS 2,600,130 6/1952 Schilling 229-29 X 2,777,629 1/1957 Osteen 229-45 X 2,974,847 3/1961 Hurn et al. 229-29 X 3,116,007 12/ 1963 DEsposito et al 229-45 3,207,409 9/ 1965 Reifers et al 229-29 X 3,223,306 12/1965 Alsman 229-2.5 3,264,120 8/ 1966 Westcott 229-25 JOSEPH R. LECLAIR, Primary Examiner. DAVIS T. MOORHEAD, Examiner. 

1. IN A MOLDED EGG CARTON COMPRISING A TOP SECTION INCLUDING A COVER HAVING A FRONT WALL, A REAR WALL AND TWO SIDE WALLS; AND A BOTTOM CELLULAR SECTION HAVING A FRONT SIDE, A REAR SIDE AND TWO ENDS AND CONNECTIVELY HINGED TO SAID COVER ALONG THE MARGIN OF THE REAR SIDE OF THE BOTTOM SECTION TO THE MARGIN OF THE REAR SIDE OF THE COVER, THE IMPROVEMENT WHICH COMPRISES A LOCKING ARRANGEMENT FOR SECURING SAID TOP AND BOTTOM SECTIONS IN A CLOSED RELATIONSHIP, SAID LOCKING ARRANGEMENT COMPRISING (1) A BOTTOM LOCKING FLANGE HAVING (A) ONE OF ITS LONGITUDINAL EDGES HINGED TO THE LONGITUDINAL EDGE OF THE FRONT SIDE OF SAID BOTTOM CELLULAR SECTION, AND (B) AN OPPOSITE LONGITUDINAL EDGE; SPACED-APART RECESSES LOCATED ALONG THE LENGTH OF SAID BOTTOM LOCKING FLANGE, SAID RECESSES BEING CHARACTERIZED BY HAVING A LOCKING RIDGE LOCATED SUBSTANTIALLY ADJACENT TO SAID OPPOSITE LONGITUDINAL EDGE; AND (2) A TOP LOCKING FLANGE HAVING (A) ONE OF ITS LONGITUDINAL EDGES HINGED TO THE LONGITUDINAL EDGE OF THE FRONT WALL OF SAID TOP SECTION; AND (B) AN OPPOSITE LONGITUDINAL EDGE, SAID TOP LOCKING FLANGE BEING POSITIONABLE INSIDE OF THE FRONT WALL OF SAID TOP SECTION AND SUBSTANTIALLY IN PARALLEL RELATIONSHIP THEREWITH; SAID TOP LOCKING FLANGE BEING FURTHER CHARACTERIZED BY HAVING SPACED-APART PROJECTIONS LOCATED ALONG THE LENGTH OF SAID TOP LOCKING FLANGE, WHICH PROJECTIONS ARE ADAPTED WHEN THE CARTON IS CLOSED, FOR MATING ENGAGEMENT WITH SAID RECESSES ON SAID BOTTOM LOCKING FLANGE, SAID BOTTOM LOCKING FLANGE BEING POSITIONABLE INWARDLY TOWARD SAID CONNECTING HINGE WHEREBY, WHEN SAID CARTON IS CLOSED, SAID BOTTOM LOCKING FLANGE IS SUBSTANTIALLY ADJACENT TO THE TOP LOCKING FLANGE AND AN EDGE OF A PROJECTION IN THE TOP LOCKING FLANGE ABUTS AGAINST A LOCKING RIDGE ON SAID BOTTOM LOCKING FLANGE. 